Question

Докажите тождество: a^2 + b^2 = (a-b)^2 + 2ab

Answer 1

$a^{2}+b^{2}=(a-b)^{2} +2ab\\a^{2}+b^{2}=a^{2}-2ab+b^{2}+2ab\\a^{2}+b^{2}=a^{2}+b^{2}$